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View Full Version : Material search, 3.5" tube or pipe in 316 stainless?



vpt
03-18-2015, 05:24 PM
I have a job coming up to sleeve some cast pizza rollers with stainless. The rollers right now measure 3.5" od. Their adjustment while on the machine is maybe 3/8" each, in the end they have to turn out a perfect thickness dough sheet ( I set this for them once before and forget what the actual size is right now).

The cast rollers have plenty of thickness to them to be turned down to any size and be sleeved. In the end though the OD should be close to their original 3.5" though.

It is still an option that I am thinking about to just weld on new ends to the new stainless and simply just make "new" rollers and not mess with sleeving the old ones at all.


Either way I am looking for an outlet for decently priced 316 3.5" tube/pipe. :D I have lost all my metal links when I got my new puter. :(

Rich Carlstedt
03-18-2015, 05:53 PM
We got a lot of stainless steel pipe and fittings from Felker bros, just down the road from you.
They are a big fabricator

http://www.felkerbrothers.com/piping-products/

Rich

You are better off making new rollers IMHO

Lu47Dan
03-18-2015, 08:14 PM
The OD of 3" SS pipe (not tube) is 3.5" roughly. If you can make new ends that will hold new Food grade bearings you should be able to sneak polished SS Schd 10 - Schd 40 pipe through. You should be able to get pipe in 304 through 316 SS.
Cutting and machining it might be fun.
I think you would have a lot less time invested in making new rollers than doing all the machining to sleeve the present rollers.
Dan.

vpt
03-18-2015, 08:27 PM
We got a lot of stainless steel pipe and fittings from Felker bros, just down the road from you.
They are a big fabricator

http://www.felkerbrothers.com/piping-products/

Rich

You are better off making new rollers IMHO



Looks like they want full length orders. I really only need about 6' for this job.

I am thinking new rollers are the best idea too.

oxford
03-18-2015, 08:55 PM
Does it have to be 316? Pretty sure 304 is considered food grade, it may open up more options for you.

Lee Cordochorea
03-18-2015, 09:23 PM
There is no such thing as "food grade stainless." 316 is used in a lot of pots & pans because it withstands deep drawing so well. There are tons (literally) of 304 being used to process milk, beer, and other goodies.

Anything which can be passivated is a go.

As a sidenote, there's no such thing as "surgical steel" either.

vpt
03-18-2015, 09:55 PM
Medical grade stainless?


Any time I do food or "person involved" stuff I use 316. I haven't use 304 yet besides for exhaust on cars.

LKeithR
03-18-2015, 10:37 PM
There is no such thing as "food grade stainless."

As a technical description you're correct but 304 is so commonly used in food processing applications that many places routinely call it "food grade"--sometimes usage is as important as what the book says.

There's very little need for 316 in the food processing industry...

Lee Cordochorea
03-19-2015, 12:58 AM
As a technical description you're correct but 304 is so commonly used in food processing applications that many places routinely call it "food grade"--sometimes usage is as important as what the book says.

There's very little need for 316 in the food processing industry...
As previously noted, many pots & pans are 316. "Need" is usually based on "cost."

You'll find 347 and 430 in use as well, for stuff that gets hot. There are also martensitic grades for grinders & choppers. And knives, of course. Knives are martensitic.

What book are you referring to? I'm always interested in a new book...

vpt
03-19-2015, 07:48 AM
I guess I shouldn't be to concerned about the stainless grade as right now the rollers they use are just cast steel/iron.


On the machining side of things does one grade machine better than the other 304/316? All stainless seems to be tough to machine, I am just curious if one is considered easier to machine than the other.

With cars I always go with 304 because it doesn't corrode or turn brown like 409. I never thought about using it in food projects though.


I also didn't think the price difference between 309 and 316 was very much from the few places I was looking at. It just seemed every place I was looking, once the sizes got over 2.5" the tube/pipe sizes started to graduate by inches instead of halves.

Carm
03-19-2015, 08:08 AM
I have some experience in welding SS sanitary piping. The criterion for "food grade" material pertains to surface finish. The standard used to be 32Ra, note this is not RMS.
Any welding has to meet the same finish. In a nutshell, no voids or crevices for nasties to accumulate. Getting fabrications past inspection is a hefty portion of job cost.
A common machining grade of SS is 302. But you really need to know service conditions; strong bases, acids and chlorine can damage some grades easily.

You might want to verify the existing rollers since cast iron is an approved metal for food, again depending on service- whereas steel?

Duffy
03-19-2015, 09:21 AM
Ever think of exhaust piping for trucks? It seems to come in a range of sizes, in both steel and stainless steel of some type.

vpt
03-19-2015, 09:54 AM
I have some experience in welding SS sanitary piping. The criterion for "food grade" material pertains to surface finish. The standard used to be 32Ra, note this is not RMS.
Any welding has to meet the same finish. In a nutshell, no voids or crevices for nasties to accumulate. Getting fabrications past inspection is a hefty portion of job cost.
A common machining grade of SS is 302. But you really need to know service conditions; strong bases, acids and chlorine can damage some grades easily.

You might want to verify the existing rollers since cast iron is an approved metal for food, again depending on service- whereas steel?

The machine and rollers they use now are near 80 years old I have been told. All I did for them last time was skim off the roller and make them smooth again so the dough wouldn't stick to them. All I knew is the material came off the roller in powder.



Ever think of exhaust piping for trucks? It seems to come in a range of sizes, in both steel and stainless steel of some type.


I did look, I think there was some options for 304 but when I was looking for 316 I couldn't find anything in 3.5". If 304 is all ok I may go that route.

Carm
03-19-2015, 10:03 AM
"The machine and rollers they use now are near 80 years old I have been told. All I did for them last time was skim off the roller and make them smooth again so the dough wouldn't stick to them. All I knew is the material came off the roller in powder."

Sounds like cast iron. Something to think about if you go SS, will dough stick to it?

Rich Carlstedt
03-19-2015, 04:25 PM
Andy
We used SS almost exclusively in my last job. Mainly 304, recently building a production line
304 is less expensive than 316 for one. ( Like 2/3rd's the cost )

The second consideration is the environment.
304 is not as good as 316 in an acid based operation.
Probably nothing to worry about if you are rolling dough, but if you were pump acidic water, then it would be worth the extra $$$
to get longevity.

The last consideration is stress cracking .
I am not qualified to comment on it, but it is a consideration for both welding , and where the element Chlorine ( acid !) is present and 316 is better from what I know.

Rich

oxford
03-19-2015, 06:19 PM
VTP, FWIW, I work in a plant that manufactures machinery for the baking industry, all the stainless we use is 304 for contact and non contact surfaces, I have never seen 316 there. Sticking of the dough could be a concern, usually on a non coated surface there needs to be enough flour or oil to prevent sticking. The rollers we make for sheeter heads actually have a Teflon tube pressed onto the roller, some of our other contact areas have a sprayed on Teflon coating to prevent sticking.

gzig5
03-19-2015, 07:42 PM
Speedy Metals in Milwaukee has both tube and pipe in 3.5". Material grade is 304.

http://www.speedymetals.com/c-8276-round-tube.aspx?thickness=3.5
http://www.speedymetals.com/c-8275-round-pipe.aspx

wierdscience
03-19-2015, 11:07 PM
On the machining side of things does one grade machine better than the other 304/316? All stainless seems to be tough to machine, I am just curious if one is considered easier to machine than the other.



They both machine equally well,neither is really worse than the other.That said,if you run insert turning tools by all means buy the correct insert made specifically for SS.

The two biggest problems machining it are edge welding where the material cold welds to the cutting edge and poor chip breaking were the swarf comes off in long strings.Having the correct insert will mitigate if not eliminate both issues.

vpt
03-20-2015, 08:24 AM
Thanks for all the replies!


The reason they have dough sticking problems with the cast rollers (they say) is because they eventually get gouged up over time just from scraping them and cleaning. They tell me the dough then sticks in the "rough spots" first starting out as a small piece which grows and gets smeared by the teflon scrapper bars that constantly ride on the rollers, and it turns into a mess. They do use LOTS of flour all the time while running. The machine is usually just white with flour when I get it to do maintenance.

I did think of and mention (to the owners) the possible use of teflon sleeves over the cast rollers. I am just concerned that they as well will get gouged up and rough eventually, possibly faster because they are just a "plastic". My thinking is that the stainless will hold up much better to any scraping and over all use. I plan to make the stainless rolls a near mirror finish, I don't think there will be dough sticking problems with the stainless (hopefully) with the amount of flour they use.

Hopefully this will be a one time fix and all will be good after this. Because of that the extra cost for 316 wouldn't mean anything to the guy so long as it works like it should. At 6' of material from what I see the biggest cost difference may only be $100 at most. I feel it would just be nice to have the piece of mind that I used the best I could in the event that something doesn't work out or something does happen to the rollers eventually I wouldn't be able to second guess my choice of using 304. I mean the machine and rollers I highly doubt ever see any sort of acids but it would be nice to not have to worry if it does. I do appreciate the info from the food guys though that 304 is ok to use in food products! Love the vast knowledge here!

WS: Good to know there are ss inserts! I normally don't use carbide but just might for a job like this. My poor atlas! lol

Carm
03-20-2015, 10:36 AM
The only way the dough would be acidic is if the water is acid. I doubt that's a problem but 80 years is a long time.
I think you should make some scrapers for the clean-up crew so they don't bugger the roll(s). Lots of stiff food grade plastics, cheaper to throw them away than do the roll.

oxford
03-20-2015, 04:52 PM
I did think of and mention (to the owners) the possible use of teflon sleeves over the cast rollers. I am just concerned that they as well will get gouged up and rough eventually, possibly faster because they are just a "plastic". My thinking is that the stainless will hold up much better to any scraping and over all use.

The Teflon will get gouges in it if not careful, scrapping is a no no but a light careful cleaning with some scotchbrite would be ok. We do use a scraper blade on the Teflon rollers to "peel" the dough off. They are also Teflon coated and get milled down to a blunt knife edge but we try to shoot for .002"-.003" clearance between the roller and scraper. The worst thing for the rollers is when the fresh dough is not cleaned off after a run is finished and is started up with hard pieces left in it the next day. The Teflon does wear though, stainless would be better for long term.

vpt
03-20-2015, 08:02 PM
Good info Oxford, thanks! This machine has constant teflon scrapers that are set up pretty close tot he rollers that stay on the machine all the time. Then they tell me at the end of the day and during running if it gets gumbed up they use plastic hand scrapers to scrap the rollers directly. Somehow they put scratches, gouges, and lines in the rollers that capture dough and act as a sticky spot. They say the smoother the surface (they have had these cleaned up many times) the better they work. I tried and tried an never could get a total satisfactory finish in the cast rollers. All this added up to me thinking stainless would work better all around. Should be more durable against the gouging and scratches, and I know I can get a mirror finish out of it if I want to.

Rosco-P
03-20-2015, 08:28 PM
Getting the existing rollers ground is not an option? How do they manage to scratch and gouge a cast iron surface with a plastic scraper? Is someone not admitting to using a fireman's axe on the dough rollers?

vpt
03-23-2015, 08:27 AM
The existing rolls haven't ever been "ground" but they have been turned, sanded, and worked over with decreasing media pads on an angle grinder down to a near polish. I believe one time I did set up a grinder in the tool post and trying that without much improvement. Either way every time they left here they were smooth as I feel cast can get.

How they gouge them up I really have no idea. I did figure out some of the lines that get cut/gouged into the rollers comes from the plastic scrapers that are permanently on the machine. Not that they should be touching the rollers all the time but I think they get some build up on them sometimes and I think they might get hit with things or adjusted by accident to rub on the rollers causing some grooving.


How the actual divots get in the rollers sometimes I have no clue.

Carm
03-23-2015, 09:53 AM
I've been baking a loaf of bread a week for the last twenty + years. I can tell you, dough that doesn't get cleaned up while still having a bit of moisture is incredibly tenacious, probably even more so on a "porous" material like cast iron.

oxford
03-23-2015, 09:22 PM
Carm, you are correct, dough can wreck havoc on steel and aluminum.

VTP, if you ever seen bakery people in action you would understand. They are bakers for a reason.

vpt
03-24-2015, 08:51 AM
I did get a demonstration the first time I went to see the roller problem. I didn't see any problems with how they were doing it at that time but like anything you don't know what goes on when no one is looking. I am sure too on late nights the kids might want to see what can be squished in the rollers.

All of this is part of the reason I want to make them up or sleeve them in stainless. It should hold up much better, work better, be easier to smooth out and polish, and be easier to clean.

They did mention that they hate how loud the machine is (driven by a chain) and I mentioned I could basically build a whole new machine and possibly use a timing belt sort of setup to quiet it down. He was interested at the time but then looking at numbers like most customers they then decide to just rebuild the old machine over and over again. Plus the chain system is quite dirty, the flour dries it out so it gets louder and louder, just not a great setup. Some day I feel he is going to just ok the build and have it over with. :D